The research will be carried out in 700 homebound elderly patients (mean age-80 years; range- 60-101 years). The majority of these patients are extremely frail; three-quarters are female. Some 42 percent are minority individuals (primarily African Americans); and half have extremely low incomes. Most data will be collected at in-home visits by trained interviewers using standardized or validated instruments and protocols; blood samples will be drawn by experienced phlebotomists. The study patients are currently served by the Boston University Geriatric Services, which includes the Boston University Home Medical Services (HMS) and the Boston City Hospital Home Care Program. HMS was established in 1875 and is the oldest program of physician home services in the United States. This study offers a unique opportunity to examine the health-related determinants and consequences of malnutrition in an existing cohort of ethnically diverse, inner-city elderly who are at high risk for major nutrional problems. Among the particular strenghts of the research are the availability of a large, well-defined study population of frail, homebound elderly; the inclusion of the oldest; the multidisciplinary and experienced research team; the thorough prospective investigation of nutrional status; the comprehensive evaluation of nutritional, metabolic, functional, clinical, and health outcome variables and mortality; the formulation of a limited and focused set of key hypotheses; and adequate study power for each aim.